Device for controlling the delivery of a reciprocating pump

ABSTRACT

A DEVICE FOR CONTROLLING THE DELIVERY OF A RECIPROCATING PUMP COMPRISES A CONTROLLED BY-PASS VALVE CONNECTED TO AN ELASTIC MEMBER MOUNTED IN A HOUSING OF THE DEVICE, THE BY-PASS VALVE DEFINING AN INNER SPACE IN THE HOUSING SEPARATED FROM THE WORKING CHAMBER OF THE PUMP. THE ELASTIC MEMBER RECEIVES PRESSURE ON ONE SIDE THEREOF FROM A SOURCE OF POWER AND PRESSURE ON THE OTHER SIDE THEREOF FROM THE INNER SPACE. THE SURFACE OF THE ELASTIC MEMBER, WHICH IS OPPOSITE THE SURFACE FACING THE INNER SPACE, FORMS, TOGETHER WITH THE HOUSING, AN OUTER SPACE OF A VARIABLE VOLUME WHICH IS HERMETICALLY ISOLATED FROM THE INNER SPACE.

Feb. 2, 1971 I BRlTVlN I 3,560,112

I DEVICE FOR CONTROLLING THE DELIVERY OF A RECIPROCATING PUMP Filed Sept. '5, 1968 2 Sheets-Sheet 1 Feb. 2, 1971 BR|TV|N 3,560,112

DEVICE FOR CONFROLLING TEE DELIVERY OF A RECIPROCATING PUMP Filed Sept. :3, 1968 2 Sheets-Sheet 2 3,560,112 DEVICE FOR CONTROLLING THE DELIVERY OF A RECIPROCATING PUMP Lev Nikolaevich Britvin, Ul. Dybenko 12, kv. 51, Moscow, U.S.S.R. Filed Sept. 3, 1968, Ser. No. 756,965 Int. Cl. F0411 11/00, 49/00 US. Cl. 417-275 6 Claims ABSTRACT OF THE DISCLOSURE A device for controlling the delivery of a reciprocating pump comprises a controlled bypass valve connected to an elastic member mounted in a housing of the device, the by-pass valve defining an inner space in the housing separated from the working chamber of the pump. The elastic member receives pressure on one side thereof from a source of power and pressure on the other side thereof from the inner space. The surface of the elastic member, which is opposite the surface facing the inner space, forms, together with the housing, an outer space of a variable volume which is hermetically isolated from the inner space.

The present invention relates to reciprocating pumps, and, more particularly, to devices for the control of the delivery thereof.

Known in the prior art is a device for controlling the delivery of a reciprocating pump, the housing of said device, connected to the pump working chamber, having an inner space with a resilient member and a controlled bypass valve disposed between the inner space and the pump working chamber.

A disadvantage of the known device is that its inner space is not completely sealed, thus preventing the use of said device for pumping aggressive, toxic, radioactive, highly odorous and other similar liquids, both pure and contaminated.

Another disadvantage of the known device is that due to friction forces arising in the movable sealing members of the bypass valve drive, it does not provide for a high precision of the control of the pump delivery.

An object of the present invention is to provide such a device for controlling the delivery of a reciprocating pump, which makes it possible to insure a precise manual, remote and automatic control of the pump delivery.

Another object of the present invention is to provide such a device which can be used when pumping aggressive, toxic, radioactive and similar liquids of different viscosity, both pure and contaminated.

In accordance with the afore-said and other objects there is proposed a device for controlling the delivery of a reciprocating pump, wherein, according to the present invention, the controlled by-pass valve is connected to an elastic member mounted in the housing of the device and receiving on one side the pressure from a source of power, and on the other side the pressure of the inner space. The surface of the elastic member, opposite the surface facing the inner space, forms together with the housing of the device an outer space of a variable volume, said space being hermetically isolated from the inner space.

It is expedient to make the elastic member as a men1- United States Patent 3,560,112 Patented Feb. 2, 1971 brane secured along its circumference in the housing of the device.

It is also expedient to make the elastic member as a bellows, one end portion of which has a dead face connected to the by-pass valve, and the other end portion of which is rigidly connected to the housing of the device.

When pumping highly contaminated or aggressive liquids, it is expedient that an elastic diaphragm be placed between the by-pass valve and the pump working chamber, and the space defined by said diaphragm be filled with a neutral liquid.

It is expedient to use gas or liquid supplied into the space of a variable volume as a source of power affecting the elastic member, the pressure of said gas or liquid being varied within the required range by means of any known device.

It is no less expedient to make the source of power affecting the elastic member as a pneumatic cylinder having its rod connected to the elastic member.

It is also possible to make the source of power affecting the elastic member as a spring.

The device made in accordance with the present invention makes it possible to bring down the cost of pumping installations, particularly when exercising remote or automatic control, and to increase the precision with which the parameters of the technological process are maintained. The device can be most effectively employed for carrying out rapid technological processes.

The following description of an exemplary embodiment of the present invention is given with reference to the accompanying drawings, wherein:

FIG. 1 is a side view in section of a first embodiment of a device for controlling the delivery of a reciprocating pump, in accordance with the invention;

FIG. 2 shows a second embodiment of the device;

FIG. 3 shows diagrammatically the device with the pump working chamber according to a third embodiment; and

FIG. 4 shows the same, in a fourth embodiment.

The device for controlling the delivery of a reciprocating pump comprises a housing 1 (FIG. 1) connected to the pump working chamber 2 (only a portion of which is shown in the drawing). The housing 1 has an inner space 3, a portion of which, defined by a sealed diaphragm 4, is filled with a gas, thus forming a pressure chamber 5.

Mounted between the chamber 5 and the working chamher 2 is a controlled bypass valve 6.

The housing 1 has a membrane 7 secured along its circumference therein, said membrane 7 being used as a resilient member and connected to the by-pass valve 6. The surface of the membrane 7, opposite to the surface facing the by-pass valve 6, forms together with the housing 1 of the device an outer space 8 of a variable volume, said outer space 8 being hermetically isolated from the inner space 3 by the membrane 7.

The outer space 8 is connected to a power source 10 by means of a channel 9. The pressure of gas or liquid used as the source of power affecting the membrane 7 is varied within the required range by means of any known device, for instance, by a pressure reduction means.

The membrane 7 receives on one side the pressure from the power source 10, and on the other side the pressure of the inner space 3.

The inner space 3 directly adjoining the by-pass valve 6, is connected to the inner space 3 located under the diaphragm 4, by means of channels 11 provided in a stop member 12 limiting the displacement of the diaphragm 4.

The pressure chamber 5 is filled with gas through a nipple 13.

The device is connected to the pump working chamber 2 by means of a flanged or threaded joint.

In the second embodiment of the invention (wherein structure corresponding to that in FIG. 1 is given the same reference numeral with a prime) the elastic member is made as a bellows 14 (FIG. 2), one end portion of which, protruding into the inner space 3, has a dead face connected to the valve 6'.

Used as the source of power acting on the bellows 14 is a spring 15 whose adjustment is carried out by means of a servocylinder. However, said adjustment may be performed by means of any other known method as well.

In this case gas or liquid supplied through the channel 9 may also be used as the source of power in the manner of FIG. 1.

In the third embodiment of the invention in FIG. 3 (which is similar to FIG. 1 and uses the same numerals for the same structure and double primes for modified structure) there is provided a construction to provide a dependable operation of the device when pumping highly contaminated or aggressive liquids. Thus, a separating elastic diaphragm 16 is mounted between the working chamber 2 and the by-pass valve 6. The space in the housing 1, formed between the diaphragm 16 and the by-pass valve, as well as the inner space 3 of the device, are filled with a constant quantity of pure neutral liquid, preferably of low viscosity.

In this case, the source of power 10" effecting the elastic member 7" is a pneumatic cylinder 17, the rod of said pneumatic cylinder 17" being connected to the elastic member 7".

In the fourth embodiment of the invention, in FIG. 4, which is similar to FIG. 3, the same numerals are used for the same structure and triple primes are used for similar structure. A spring 18 (FIG. 4) with a constant spring valve is used as the power source 10" acting on the elastic member 7 with one and the same force, the control of the pump delivery being effected in this case by varying the pressure in the chamber 5" by means of any known method, for instance through varying the volume of the chamber by fluid control means 23.

The device for controlling the delivery of a reciprocating pump operates as follows reference being made to FIG 1.

To effect a controlled change of the pump delivery, the device is connected to the pump working chamber 2. With the piston 19 (FIGS. 3 and 4) performing its pressure stroke, the liquid forced by said piston out of the working chamber 2 is delivered via the normally open by-pass valve 6 into the inner space 3, and passing through the channels 11 changes the volume in chamber 5 by displacing its diaphragm 4, the normally open position of the valve being provided by the power source 10 through the elastic member 7.

As the liquid is supplied from the working chamber 2 into the inner space 3, and the volume within chamber 5 is reduced, the pressure in the inner space 3 increases. The pressure continues to increase until the force acting on the elastic member 7 from the side of the inner space 3 slightly exceeds the force acting on the elastic member 7 from the side of the power source 10.

The elastic member is moved toward the space 8 of a variable volume, and the by-pass valve 6 is brought onto a seat 20, thus discontinuing the delivery of liquid into the inner space 3 of the device. With the by-pass valve 6 closed, the pressure in the working chamber 2 increases and reaches the pressure valve in the pumping main 21 (FIG. 3), whereupon the liquid starts being delivered through a delivery valve 22 into the pumping main 21 until the pressure stroke of the piston 19 is completed. During the suction stroke of the piston 19, the by-pass valve 6 is opened and, due to the pressure in the chamber 5, the liquid is supplied from the inner space 3 into the working chamber 2 until the diaphragm 4 rests upon the stop 12, whereupon the pressure in the working chamber 2 is reduced to the pressure in the pump admission main 23. Then, an admission valve 24 is opened and the working chamber 2 is filled from the admission main 23. After this the whole process is repeated.

By varying the value of the force acting on the elastic member from the side of the power source 10, it is possible to change the moment of the by-pass valve 6 during the pressure stroke of the piston 19.

When the power source 10- acts on the elastic member with the minimum possible force, the by-pass valve 6 will be closed at the very beginning of the pressure stroke of the piston 19, and the delivery will be maximum. An increase in the force acting upon the elastic member from the side of the power source 10 will correspondingly postpone the moment of closing of the by-pass valve 6 and, hence, will decrease the pump delivery.

With the valve opening taking place during the pressure stroke directed towards the inner space 3 (FIG. 4), the control of the moment of the valve closing is effected in the course of the suction stroke, i.e. while'the liquid is being delivered from the inner space 3 into the working chamber 2.

The valve starts closing when the forces acting upon the elastic member 7" from the side of the inner space 3 and from the side of the space 8 of a variable volume, where the spring 18 is disposed, are balanced.

Though, for the sake of clarity a specific narrow terminology has been used for the description of the aforegiven embodiment of the present invention, it is to be borne in mind that the invention thus described is not to be limited by the terms so adopted as each such term embraces all equivalent elements operating in similar manner and used for same purposes.

Though the present invention has been described with reference to a preferred form of construction for carrying it into effect, it is evident that different modifications and variations may be made without departing from the spirit and scope of the invention, as those skilled in the art will easily understand.

What is claimed is:

1. A device for controlling the delivery of a reciprocating pump having a working chamber with a slidable piston therein, said device comprising a housing connected to the working chamber of said pump; a controlled by-pass valve mounted in said housing, said housing defining an inner space separated from said working chamber by said by-pass valve; a resilient member disposed in said inner space; an elastic member disposed in said housing and connected with said by-pass valve; said housing and elastic member defining an outer space of a variable volume hermetically separated from said inner space; and a source of power connected to said outer space of variable volume, said elastic member receiving on one side thereof pressure from said source of power and on the other side thereof the pressure in said inner space.

2. A device according to claim 1, wherein said elastic member in said housing comprises a membrane secured along its circumference in the housing.

3. A device according to claim 1, wherein said elastic member in said housing comprises a bellows having one end portion which is a dead face and the other end portion rigidly connected to the housing.

4. A device according to claim 1 comprising an elastic diaphragm between the by-pass valve and the pump working chamber enabling the latter to operate with contaminated and corrosive fluids, the space defined by said diaphragm on the side thereof remote from the working chember being filled with a neutral liquid.

5. A device according to claim 1, wherein said source 2,543,828 3/1951 Brown 103--37 of power comprises a pneumatic cylinder with a rod con- 2,619,907 12/ 1952 Paterson 10337 nected to said elastic member. 2,711,697 6/ 1955 Gibbs 103223 6. A device according to claim 1, wherein said source 3,261,330 7/ 1966 Avant 1036 of power comprises a spring connected at one end portion r 2,417,474 3/ 1947 Feroy 10338 to said elastic member and at its other end portion to 0 i h i HENRY F. RADUAZO, Primary Examiner References Cited U S CL X R UNITED STATES PATENTS 92-60.5

204,747 6/1878 Maxim 103-37 10 1,708,306 4/1929 Giesler 103223 

